Scientists Find Gene Differences in Nonsmokers With Lung Cancer

MONDAY, Nov. 12 (HealthDay News) -- Three genetic regions associated with increased lung cancer risk in Asian women who have never smoked have been identified by an international team of scientists.

They said their findings provide further proof that the risk of lung cancer among people who never smoked, especially Asian women, may be associated with specific genetic characteristics that distinguish it from lung cancer in smokers.

The researchers analyzed data from 14 studies that included a total of about 14,000 Asian women (6,600 with lung cancer and 7,500 without the disease). The team found that variations at three locations in the genome -- two on chromosome 6 and one on chromosome 10 -- were associated with lung cancer in Asian women who never smoked.

The discovery on chromosome 10 was especially important because it has not been found in previous research, according to the study published online Nov. 11 in the journal Nature Genetics.

"Our study provides strong evidence that common inherited genetic variants contribute to an increased risk of lung cancer among Asian women who have never smoked," study co-author Dr. Nathaniel Rothman, a senior investigator in the division of cancer epidemiology and genetics at the U.S. National Cancer Institute, said in an institute news release.

"These variants may also increase lung cancer risk associated with environmental factors, such as environmental tobacco smoke," he added.

The researchers did not find an association between lung cancer risk in Asian women who had never smoked and variations at a location on chromosome 15 that has been linked with lung cancer risk in smokers. This provides further proof that the genetic variation on chromosome 15 may be smoking related, the authors said in the news release.

The research team also found some evidence that Asian women with one of the newly identified genetic variants may be more vulnerable to the effects of secondhand smoke. But more research is needed to confirm this.

Lung cancer among people who have never smoked is the seventh leading cause of cancer death worldwide, according to the release. Historically, most lung cancer diagnosed among women in Eastern Asia has been among those who never smoked. The three genetic variations identified in this study have not been associated with lung cancer risk in other populations.